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Injective type family syntax accepted without TypeFamilyDependencies

    • Closed Issue created by Jan Stolarek @jstolarek

    This program compiles fine although it names the result type variable, which is a piece of syntax that should only be available with TypeFamilyDependencies (injective type families):

    {-# LANGUAGE TypeFamilies #-}

module Foo where

type family F a = r where
    F a = a

    If I say:

    type family F a = r | r -> a where
    F a = a

    only then the definition is rejected.

    Trac metadata
    Trac field Value
    Version 8.0.1
    Type Bug
    TypeOfFailure OtherFailure
    Priority low
    Resolution Unresolved
    Component Compiler (Parser)
    Test case
    Differential revisions
    BlockedBy
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    Blocking
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    Operating system
    Architecture
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